Production of flavanthrone



4 liefli- YIatmecl oct; 13, 1931 Y Y o CHEMICAL oo., INC.; yo1? YORK,`N.ELY.,VA coRBRATIN-QF NEWJYQRK k jow n ,In the vinauuifaiotrufle'thiol produetiou of fla- *van'throng'it here been heretofore pifopoysed lto Slowly addamino-athfaqui'norie to a, 'Solumay-beamed fees, pea, an mum@- m'esyor minimizesfthe Exmpleflw aftsfg@my www! ride are, dssolvedin 2501 parts of dry ftrocont aiming 88 parts"V of f a't'imony' pent'ahlo'- ride; 2 Toth@- Weilfstirred nitrobnzene sold# eb "subs'tantially allfabsorbedto form a olution l ture'ffabbt 1500400 there *is glazig-C1T Q5 basis) yand the mixture, isftheil irupiilly;l heat-y Whieh the reaction iS ear'ri'i th' apparatus in "out 'bei'ligfjcouf I reaction mixture, Y togetherV with 'heated with a, condenser,soarragdfhutfh jY 'taining `thejLmixireg la temprature v gj-fl @-160o C. for @toman-hour, until ithje Y 110011511091415? G. and' finned' fom'thejsepwith hot nitobe'zene'f( bout :1105-1150 C.)

(3;).- .It is then dri'e'clin at vacuum on in any Produc@ iS 0f, @Superiorqualityprapurity. 1 l 111 theiabov@ examples to solution. After this salt is formed, the reaction mass is then further heated to a higher temperature, about 210 C., to edect the decomposition of the salt with formation of fiavanthrone which separates out, it being insoluble, or nearly so, in `hot nitrobenzene. In filtering off the flavanthrone from thehot nitrobenzene reaction mass, a purification is eected since the impurities remain mostly in-solution in the hot nitrobenzene.

portant that as much as possible of the water and hydrogen chloride formed during the* reaction be removed from the field of action at all stages of the process, particularly duringthe formation of the avanthroneantimony pentachloride double. salt, that is, at about 100 C. or below, and be not permitted to return by reflux lor otherwise to the reaction-mixture, otherwise the `yields of flavanthrone will be materially lessened and the quality'of the dye injured. It is lfurther importantgthat the final tempera-ture does not exceed about 210 C., which is below the actual boiling point of the mixture, otherwise the product will be less pure andv also difcultlto iilterand wash.

,The lflavanthrone antimony pentachloride :salt decomposesfquite rapidly at about 200 C. andthe temperature around this point vshould be carefully raised to prevent a too vigorous reaction. f The filtration `of the fla- -vanthrone should be promptly made from the hotso'lution or the purityv of the dye is apt to be affected. c f

Itvmay bey further pointed out that a inodification of the invention' which comprises heating 2-aminoanthraquinone in Vadmixture ,with a nitrobenzene solution of antimony Vpentachloride to, a temperature of aboutl210 C.' without maintaining the mixture for any suitable period of time at the intermediate Vtemperature ofvaboutlio to 160 C., but during which operation, however, the water and hydrogen chloride are eliminated andrem'oved from the field of action, produces fairly good results. Nevertheless, the results so obtained are not as favorable as those obtained by the invention when carried out assillustrated in the example where the step of holding the mixture at the intermediate temperature is employed.

Itis understood that the details in this process can be varied considerably without l departing from the spirit or scope of the invention. For example, an impure 2-aminolanthraquinone may be used, particularly if vthe impurities are of a character which produce very little or no effect on the'quality of the flavanthrone produced; the proportions of nitrobenzenevand of antimony pentachlo- 'tered from the nitrohen'zcneV at l or around A .-5 and hydrogen chloride. evolved during the In carrying out the, invention, it is izn-V lcourseof the reac`tion.v Y

200 to 210 C. or at temperatures between or as low as about 90 to 100 C.

I claim:

1. In' the production of fiavanthrone by a process which comprises heating 2-aminoanthraquinone with antimony pentachloride in the presence of nitrobenzene, the improvement which comprises permanently removing fromthe sphere of the reaction the water course of the reaction.

2. In the production of flavanthrone by a process which comprises heating 2-aminoanthraquinone with antimony pentachloride in the presence of nitrobenzene, the improvement which comprises heating the :reaction mixture at a temperature of about 205 to 210 C., and during the course ofsaid heating operations Vpermanently removing from the sphere of the reaction the water and hy- Het drogen chloride evolved. g d

3. In the production of flavanthrone by a process which comprises heating'2-aminoanthraquinone with antimony pentachloride in the presence of nitrobenzene at a tempera- Loo ture of about 'to 160 C., the improvement whichlcomprises Vpermanently removing" from the sphere of the reaction the water andhyd'rogen chloride` evolved during the 5.VA In the y production ofl Aflava'nthrone by heating 2-aminoanthraquinone withV antimony pentachloride inthe presence of ni- 'trobenzene at a temperature koflabout 145 to C., the improvement which comprises N11o heating the reaction mixture containing a flavanthrone antimony plentachloride salt and nitrobenzene at a temperature not to exceed about 210l C., whereby flavanthroneis produced, and removing from the sphere of l ther'eaction the water vapor and hydrogen chloride evolved during the course of the reaction.

6. In the production of, flavanthrone, a process vwhich comprises heating 2-amino- .i anthraquinone with antimony pentachloride V inthe presence of nitrobenzene to a temperature of about 14L5160 C., removing from the sphere of action the'water and hydrogen chloride evolved during the'force of the reaction,lmaintaining this temperature until i the evolution of- Vwater and, hydrogen chloride has' practically ceased, then further heating the mixture and` maintaining the temperature at abo11t`-2052m10 GQ-until the ,130

v during the course yof the reaction removingv kformation of la'vanthrone` is substantially complete.

7 In the production heating 2-amino`anthraquinonef Withi antimony pentachloride inthe ypresence of nitrobenzene, the improvementv Which--V comprises the employment in the courseof the reaction of a current of inert gas to assist-infthepermanent removal of the-Water and` hydrogen I. so'

chloride formed in the reaction. c Y n. 8. In the production of .iiavanthrone by a process Vwhich comprises heating l2-a'minoanthraquinone With antimony pentachloride in the presence of nitrobenzene, the'improvement 4which comprises heating lthe reaction. `mixture ata temperature notfexc'eeding about 210 C., and permanently removing from the spherejof the reaction-the Water vapor and Yhydrogen chloride evolved during the course of the operation by means of a current of inert gas. U; j

9. In the production of lavanthrone'by'av process Which comprises heating'2-aminoanthraquinone Withantimony pentachloride in ythe presence of nitrobenzene,1the improvement which comprises heating the. reaction mixture at atemperature not exceedingabout 210 C., and permanently removing from the sphere of thel reaction thevvater vvaporfand hydrogen chlorideevolved during the course.

of the operation by ypassing acurrent of Aair i overthe surface of the reaction mixture. f

hydrogen chloride. I

10. Inaproc-essaccording to claimY 2 the ,f v.further improvement of, passinga current of air over the surface ofthe reaction mixtureto assist in the removal Vof the water vapor and 11. In the production-of flavanthrone by heating v2-aminoanthraquinone VWith anti'- mony pentachloride in the presence of nitroheating thecmixture and maintainingit at 'a temperaturenot to'exceed about 160 C. untilY the formation of the 'flavanthrone antimony pentachloride salt is practically complete and With the aid `of aY current of air thevvater vapor and hydrogen'chloride evolved'.VV

12. In the productionof flavanthrone mony pentachloride in the presence'of nitroheating 2-aminoanthraquinone with antibenzene, the process Which' comprises completing the reaction to Aform liavanthrone and f then promptly separating the precipitated flavanthrone from the nitrobenz'ene at a tem- ,Y perature of about to 120 C. l f 'f 15. In .the production of flavanthrone, a process which comprises mixingv2-aminoanrthraquinone with antimonylpentachloride in:` kthe resence of nitrobenzenel at a temperature v of a out 50 to 70 C., rapidly heating "the mixture to a temperature of about 155 to i [160 C. and maintaining this temperature for about an hour, then further heating and maintaining the mixture ata temperature of about ,210"v C. for about another hour, perkmanently removing from thesphere` of the Y reaction the Water vapor andk hydrogen lchloride evolved duringthe course of saidheating operations, cooling thereactionmixture lto about to'115 C., and filtering off vthe flavanthrone. 1

16.v In the ,production Vof flavanthrone,y process which comprises mixing 2-'aminoanthraquinone vvith antimony pentachloride in Y the presence of nitrojbenzene at a temperature of Vabout 50,y to 70C., rapidly heating the mixture to Va temperatureof about to G.- an'd'maintaining this temperature lfor about an hour, then further heating and maintaining the mixture at a temperature of` l -aboutf210 "y for about another hour, passingl a currentof air over the surface;` ofthe re- Y action mixture throughout the course of the' 100y l reaction in orderto assist inv theperrnanent removal of' the Water vaporfand hydrogen `"'L-V il 5 chloride evolvedythen cooling theA reaction"V mixture/to about 110 to 11.5CJ, and promptcoverl the avanthrone.

' In testimony whereof I affix my signaturel WILFRED M.V MURCH; y

benzene, the processA Which comprises com- Y l I c, pleting the reaction to formvflavant-hron'e and thenseparating the precipitated flavanthrone from the nitrobenzeneatJa'temperature of about 90-120 C.

13. In the production of llavanthrone-by I heating 2-aminoanthraquinone y yvvith ,j vanti'- mony pentachloride yinthe presence of nitrobenzene, .the processlvvhich :comprises com-l' v v y pleting the reaction to form avanthrone and'.l 1 then separating 'the precipitated ilavanthrone l from Vthe nitrobenzeney atfa temperature.. 0i .7'-

c ly submitting said mixtureV to filtration tore- .1705.1 benzene, the improvement Wh1ch1compr1ses* v 

